Interactions of growth regulators, explant age, and culture environment controlling organogenesis from lettuce cotyledons in vitro

Abstract

Organogenesis in cultured Lactuca sativa L. cv. Grand Rapids cotyledons was controlled by growth regulators and influenced by explant age as well as culture environment. Control explants formed roots with a low frequency. Exposure to indoleacetic acid (IAA) greatly stimulated root initiation. Kinetin (K) applied singly or in combination with IAA induced bud formation. Benzylaminopurine (BA) also caused bud initiation. Root and shoot initiation was optimal with 4-day-old explants. Organogenesis declined with older explants. More buds formed in light than in darkness. Other environmental variables tested had no marked effect on K-induced bud initiation. Control explants on medium containing no growth regulator never formed buds.